Grassac was the seat of an archpriest who had been given in 1097 by Bishop Adhémar to the Abbey of Bourgueuil which united it to its priory Notre-Dame de Beaulieu in Angoulême. The church was enlarged, after the damage of 1570, by a north aisle which was to be vaulted with ribs. The vault and various restoration works were undertaken in the 19th century. The plan of the building is that of an enlarged rectangle with a bay under a bell tower and an apse in the extension of the initial nave. This first nave supported by flat buttresses and a projecting buttress from the 17th century, is vaulted by a flat plaster cradle. The bay under the bell tower is vaulted with a stone dome on horns, pierced with a hole for the bell and decorated with a false sky.